The speakers will be susceptible to the same kind of interference as your cordless phone. Make sure you have the phone and speakers set to different channels or you could end up with a giant speakerphone. Better yet...move up to a 2.4GHz or 5.8GHZ phone. You'll have more range, and at least
your phone won't interfere with the speakers....or go for 2.4GHz speakers. These seem to get pretty good reviews.
Amazon.com: Oregon Scientific WRS368 Music Sphere Wireless Speaker with Transmitter: Electronics 
